<template>
  <div>
      <h1>当前的和为: {{sum}}</h1>
      <select v-model.number="n">
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
      </select>
      <button class="a" @click="increment">+</button>
      <button class="a" @click="decrement">-</button>
      <button @click="incrementOdd">当前和为奇数时再加</button>
      <button @click="incrementWait">等一等再加一</button>
  </div>
</template>

<script>
export default {
    name:'Count',
    data(){
        return{
            sum:0,
            n:1,
        }
    },
    methods: {
        increment(){
            this.sum+=this.n;
        },
        decrement(){
            this.sum-=this.n;
        },
        incrementOdd(){
            if(this.sum%2){
                this.sum+=this.n
            }
        },
        incrementWait(){
            setTimeout(()=>{
                this.sum+=this.n
            },1000)
        }   
    },
}
</script>

<style>
.a{
    width: 50px;
}
button {
    margin-left: 5px;
}
</style>